Fast acting ratchet wrenches are socket wrenches having a drive stud that may be rotated in one of two modes of operation, a normal mode or a fast acting mode. Examples of such wrenches are disclosed in U.S. Pat. Nos. 4,128,025 to Main et al; 4,086,829 to Hudgins; and 3,707,893 to Hofman. The wrench disclosed in the Hudgins patent includes an elongate handle having a head mounted on one end and cylindrical hand grip mounted on the other end thereof. A drive stud is mounted for rotation in the head of the wrench on an axis perpendicular to the handle, and a first beveled gear is mounted on the rear side of the drive stud. A second beveled gear is disposed for engaging the first beveled gear, and a rod is attached to and extends from the second beveled gear to a clutch assembly that is interconnected with the cylindrical grip. In the fast-acting mode of operation, the grip is rotated to rotate the rod which in turn rotates the beveled gears to rotate the drive stud. The drive stud may be rotated in the fast-acting mode of operation until a selected resistence torque is placed on the drive stud by a nut or bolt being driven at which point the clutch assembly begins to slip. The nut or bolt may then be further tightened only by oscillating pivotal movement of the handle about the drive stud in a normal ratchet wrench action. The oscillating pivotal movement of the handle will cause the drive stud to rotate relative to the head and will also rotate the beveled gears and the rod. The rod will impart a rotational force on the clutch assembly that, in turn, imparts a rotational force on the grip. The rotational force on the grip must be resisted by the user so that when the wrench is used in the normal mode, the user will maintain the handgrip in a stationary position relative to the wrench, and the clutch must slip to allow rotation of the rod.
In a alternate construction of the fast-acting wrench of Hudgins, as shown in FIG. 5, the two beveled gears may be disengaged by sliding the grip, and the rod in a direction away from the wrench head. In this configuration, use of the fast-acting wrench as a conventional ratchet wrench will not rotate the second beveled gear and the rod, but the grip on the handle is free to rotate.
The basic problem associated with fast-acting ratchet wrenches is that they tend to wear out quickly or frequently malfunction, especially after extended use. Typically, fast-acting wrenches employ a gear system that selectively engages and disengages to switch the wrench between a fast-acting mode of operation and a normal or conventional operation. [Because of the angle of the drive surfaces on the teeth of gears, a torque applied to most gear systems tends to separate the gears.] When such torque reaches a sufficiently high level, the gears will often jump out of gear, and such malfunction will chip or wear the gears. This problem is especially bothersome in fast acting wrenches that utilize beveled gearing, such as the two 45.degree. beveled gears disclosed in Hudgins. Also, repetitive engagement and disengagement of the gears will wear the gears and make them more susceptible to malfunction by jumping out of gear.
A clutch assembly that limits the amount of torque that may be applied to a gear system of a fast-acting ratchet wrench will protect the gear system to some degree, but the clutch assembly is expensive to manufacture and install in the wrench, will itself wear out quickly due to the necessary slippage in the clutch assembly, and may prevent the user from applying a desired torque to the gear system. Also, the clutch system in Hudgins may possibly be adjusted to the point that it no longer functions as a clutch, and in such a case a torque may be applied to the gear system causing the beveled gears to disengage or jump out of gear.
Furthermore, when a clutch system is provided, such as is disclosed in Hudgins, the grip trys to rotate when the wrench is used in a normal or conventional operation mode. Such rotation of the grip impairs the usefulness of the fast-acting ratchet wrench when used in the normal mode and, at a minimum, is a bother to the user.
Thus, a need has arisen for a fast-acting ratchet wrench that may be easily and reliably switched between a fast-acting mode of operation wherein a drive stud is rotated by the rotation of a handle, handgrip, or like device in a rotational axis generally perpendicular to the drive stud and a normal mode of operation wherein the drive stud is rotated by oscillating pivotal motion of the handle about the drive stud. Such fast-acting ratchet wrench needs to resist gear jumping, the damage caused by gear jumping and the damage caused by repetively engaging and disengaging a gear system. Such fast-acting ratchet wrench also needs to avoid the use of a clutch system because of their inherent expense and tendency to wear out quickly, and needs to provide structure to avoid free rotation of the handle or grip when the fast-acting ratchet wrench is used in the normal mode of operation.